title: Ultralow oxygen treatment for control of Latrodectus hesperus (Araneae: Theridiidae) on harvested table grapes.
abstract: The spider Latrodectus hesperus Chamberlin & Ivie (Araneae: Theridiidae) was subjected to low and ultralow oxygen (ULO) treatments at different temperatures. Complete control of the spiders was achieved in 24-h ULO treatments with 0.5% O2 or lower at 1 degrees C and in a 24-h low oxygen (2%) treatment at 15 degrees C. Oxygen level and temperature greatly affected spider mortality. At 1 degrees C, as oxygen level was decreased from 2 to 0.5%, spider mortality increased from 0 to 100%. At 2% O2, as temperature was increased from 1 to 15 degrees C, spider mortality increased from 0 to 100%. Grape clusters from two table grape (Vitis spp.) cultivars, 'Thompson Seedless' and 'Flame Seedless', were subjected to the 24-h ULO treatment with 0.5% O2 at 1 degrees C. The ULO treatment had no negative effects on grape quality. Because of the relatively short treatment time, effectiveness at low storage temperature and the easily attained oxygen level, we conclude that the ULO treatment have good potential to be implemented commercially for control of black widow spiders on harvested table grapes.
authors.affiliation: USDA-ARS, Crop Improvement and Protection Unit, Salinas, CA 93905, USA. yongbiao.liu@ars.usda.gov
authors.forename: Yong-Biao
authors.initials: YB
authors.lastname: Liu
authors.forename: Kent M
authors.initials: KM
authors.lastname: Daane
authors.forename: J Steve
authors.initials: JS
authors.lastname: Tebbets
authors.forename: Larry J
authors.initials: LJ
authors.lastname: Bettiga
mesh_terms: D000818:Animals; D001740:Black Widow Spider / Q000187:drug effects*; D010100:Oxygen / Q000494:pharmacology*; D010571:Pest Control / Q000379:methods*; D013696:Temperature; D013997:Time Factors; D027843:Vitis
chemical_list: D010100:Oxygen